1. Field of the Invention
This invention relates to a photographic film assemblage including a roll of unexposed film, which assemblage is adapted for use in a hand-held camera.
2. Description of the Prior Art
The present invention relates to a photographic film assemblage including a film cassette having a film exit, a film supporting spool, and a length of unexposed film coiled about the spool and having one end secured thereto and its opposite end extending to the exterior of the cassette via the exit and, more particularly, to a film assemblage of the type adapted for use with 35 mm cameras presently on the market.
Film assemblages of the type described above are generally well known and each is adapted to be located within a film cassette compartment in a hand-held camera such that the portion of film extending exteriorly of the film cassette may be run across the focal plane of the camera and attached to a film take-up reel. The loading door of the camera is then closed and the individual frames in the film are sequentially exposed as the previously exposed frames are wound upon the take-up reel. The trailing end of the film is generally fixedly attached to the spool in the film cassette in order to prevent the complete withdrawal of the film from the cassette during the exposure of the film. After the last frame has been exposed, the film is recoiled about the spool in the cassette until only the leader or leading end section of the film remains outside the cassette, or until the leading end section has been completely moved to the exterior of the film cassette. Next, the film assemblage is removed from the camera and the exposed film is processed. During processing, the trailing end of the film is detached from its spool, generally by a film cutting apparatus, such that the remainder of the processing cycle may be carried out. Accordingly, it can be seen that although the securing of the trailing end of the film to the spool prevents the inadvertent, or otherwise, complete withdrawl of the film from the cassette during exposure, one must compensate for it, the securement, by providing the processing apparatus with means for severing the trailing end of the film from the spool.
U.S. Pat. No. 4,212,527 describes a film assemblage of the type described above which includes means on the leading end of the film for preventing it from being rewound completely into a film cassette. Thus, while this feature facilitates the subsequent processing of the film, it appears that the trailing end of the film is still attached to the spool of the assemblage thereby requiring separate means in the film processor for identifying when the film has been substantially uncoiled from the spool and then stopping the motor of the film processor.
U.S. Pat. No. 4,145,133 describes a film assemblage having a cassette which rotatably supports a spool having a length of film wound thereupon, but not secured thereto. Also, the film includes means for preventing its leading end from being fully rewound into the film cassette. One problem with this assemblage is that the film may be inadvertently fully withdrawn from the cassette during its exposure thereby rendering the exposed film useless for all practical purposes.
U.S. Pat. No. 3,550,877 discloses a film assemblage including a cassette, a spool rotatably supported within the cassette, and a length of film wound upon the spool. An antibackup shuttle prevents reverse rotation of the spool to unwind the film for processing. The processing apparatus for this film assemblage includes a punch which punctures the side of the cassette and displaces the shuttle axially to an inoperative position. Here again, one has a film processor wherein a severing or cutting operation must be preformed. Not only must one continually maintain the sharpness of the cutting tool in the processor, but also there remains the problem created by fragments of the cassette, caused by the cutting or puncturing operation, entering the processor.
Finally, U.S. Pat. No. 3,978,495 shows a cassette having a spool upon which a length of exposed film is adapted to be wound with one end of the film releasably secured to the spool. However, this cassette is not part of a film assemblage of the type described, nor does it relate to the problem of retaining the trailing end of film in engagement with the spool during exposure of the film in a hand-held camera, and releasing it during processing of the exposed film.
Another problem with film assemblages of the type described is that they are not provided with means for indicating whether or not the film within the film cassette has been photographically exposed. For example, one may remove a film cassette containing an exposed roll of film from a camera and set it aside for processing at a later date. However, at this later date, the photographer may not remember if that particular film cassette contains exposed film.